1. Field of the Invention
The present invention relates to an electrophotographic copier, printer, facsimile apparatus, multifunction machine having at least two functions thereof or similar image forming apparatus. More particularly, the present invention relates to an image forming apparatus of the type including a process cartridge, which includes at least an image carrier on which a toner image is to be formed and a cleaning device including a cleaning member for removing toner left on the image carrier after the transfer of the toner image, and removably mounted on the body of the apparatus. A case included in the process cartridge is formed with a hole to pass a light beam emitted from an optical writing unit toward the image carrier therethrough.
2. Description of the Background Art
An image forming apparatus of the type described is conventional and disclosed in, e.g., Japanese Patent Laid-Open Publication No. 2003-316107. This type of image forming apparatus is configured such that a light beam, issued from an optical writing unit, is incident on an image carrier via a hole formed in the bottom wall of a case included in a process cartridge. The opening, however, is apt to cause toner leaked between a cleaning member and the image carrier to drop on the optical writing unit via the above hole. This part of toner contaminates the optical wiring unit and therefore lowers the quality of a toner image formed on the image carrier.